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Working on chicken coop design for <-20F temperatures. Need advice for winter ventilation

 
Posts: 4
Location: Ontario, Canada
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Hello everyone,

I am new to the forum, but I have been listening to the podcasts for quite a while.

I am currently working on the design of a chicken coop to host a dozen of chickens. It will be a 3.5' x 6' coop with a 20' x 8' covered run and 3 egg nests. I live in Eastern Ontario where we get periods of temperatures under -20F/-30C (without windchill) in the winter and above 90F/30C and humid in the summer. I want the coop to work well for the chickens all year and avoid heating if possible, so ventilation has to be designed carefully...

For the summer it is relatively easy, I will just have panels on hinges that I can open on 3 sides (the north-facing side will be storage for the coop) with hardware cloth to keep predators out.

For the winter it is a lot trickier. Enough fresh air supply is required to get rid of moisture and ammonia, but there should not be any draft and retaining some heat is probably good as well.
So my plan is to seal the coop as well as possible and insulate the floor, the walls and above the ceiling, to prevent drafts and help retaining the heat. The coop will have a single window, facing south, and it will have a double glass panel for better insulation. I want the ceiling to be about 1 foot above the chickens so the volume of air around them is not excessive. I will use the deep liter method.
To flush the moisture and ammonia, I wanted to install a cupola on the roof, right in the middle of the coop, which will be linked to the coop through a 4" diameter pipe.

My understanding is that the above features are generally recommended for coops, so I am quite confident about them. Regarding the cupola, what I like about it is that it will directly extract  the lighter ammonia from the coop. Also, the pipe will have horizontal openings, such that winds should not generate drafts through that opening. The part that I am less confident about is what to do for air intake. I read recommendations about openings right under the roof, but I don't like the idea too much, because it will tend to make the coop colder and more drafty during windy days. An idea I have is to create vertical air intakes under the coop, which will sit 2' above the ground, and introduce that air in the coop about 1.5' above the floor (about 0.5' under the roost bars). I could have one air intake in each one of the four coop corners. Due to the location and orientation of these air intakes, it should be much less affected by winds, so the air would mostly get exchanged through convection, the 4" cupola pipe acting as a chimney. My plan is to have the same total cross-sectional area for the air intakes as for the 4" chimney. I would also make the opening of the 4" pipe adjustable, through hinged panels right above the ceiling.

I would like to know what you think of that design. How should such air intakes that are less sensitive to winds and that introduce air lower in the coop perform with chicken compared to openings under the roof. Should the cupola with a 4" pipe be sufficient for this 3.5' x 6' coop when it is too cold outside to open the wall panels?

Thank you!
 
pollinator
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Hi Pierre-Luc, and welcome to Permies.  

First, you know you get down to -40C at times.  It's OK, you can admit it. ;)  I know we get down to that most winters in SW ON, sometimes for a week or two.  

Insulation and ventilation are pretty much mutually exclusive.  It's nice to insulate the floor of the coop, but the deep litter takes care of that.  Also, they'll happily roam around in the snow, so it's usually not a big deal.  The window doesn't need to be double glazed as any heat in the coop will go right out the top.  You also don't need a fancy cupola, just know that you need to get rid of the excess moisture and, as you know, keep the drafts off them.

I built a 4x6' coop out of 2x3 frame on 2' centers and 1/2" ply sides and roof.  I slanted the roof from 7' to 5' and kept my roosts at 2.5-3' so there was about 18" above the roosting hen to the 2" gap around the roof.  I just ran 2x3" joists on top of the coop frame for the gap and used 1/2" hardware cloth to keep out rats, weasels and opossums.  I had a couple of open cut outs that I covered with hardware cloth for more ventilation in the summer that I covered in the winter.  

Chickens come with a down coat, so they can stay pretty warm in winter.  I chose breeds with small combs, pea combs for preference.  I had a number of Chanteclers, our only Canadian breed, and they do very well in winter, as you'd expect.  I did end up with a couple of hens with big combs and they did get a little frostbite, but not bad.  In winter, they'll crowd together on the roost for warmth, squat down on their feet and tuck they're heads under their wings.  If you heat the coop and then lose power, they can't handle the abrupt change, so that'll kill them.  I took my girls through several winters like that without any issues except frozen water and eggs.  

I built a cookie tin waterer heater for underneath the plastic waterer, though I had to use 2 75W bulbs when it got down below -20C.  If you do use a cupola, make your air intake the same gaps just below the roof.  That way you'll have air stratification and it will come in under the roof and out the cupola, but the cupola should be at least 2' tall to get the right stack effect.  I've done a lot of attic ventilation analyses and stratification is  normally a bad thing, but good for livestock.  Like I said, though, it's needlessly complicated as a 2" gap 18" above chicken height (2-2.5' above the roost) works just fine.

edit:  I just wanted to add that you pretty much need to supplement light in our winters as they like 14 hours to lay well, even the Chanteclers, whatever anyone tells you. If you get them this year as ready to lay or pullets, you don't have to let them moult in the fall but next year let them moult naturally as the light wanes, then add light back gradually in the morning to get to 14 hours.  You want them to experience natural dusk as they'll naturally go home to roost and the light won't shut off all of a sudden, leaving them on the floor.
 
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My family had chickens in the 1970s in a log coop on the upper Yukon in Alaska, where it would get down below -50F and stay there for a couple of weeks at a time in January.  Under those conditions at least, ventilation was the enemy.  The goal was to seal that coop up as tightly as possible.  It was about six feet by eight feet, just tall enough for a person to stand inside, flat roof, made of about six inch logs, chinked with moss, plywood and tarpaper flat roof insulated with several inches of moss with Visqueen (plastic) vapor barrier.  There was sawdust on the floor of the coop but there was a screened bin under the perch to catch droppings.  Ammonia in the air was a definite issue, but never so much that it seemed to affect the health of the chickens.  I'm not saying any of this was a good way to do things, I'm just saying it was a way that worked and (mostly) kept chickens alive -- probably based on drawings/designs my parents saw in Mother Earth News magazine or Foxfire or a Rodale Press book.  

In the very coldest temperatures they would hang an old fashioned barn lantern (kerosine-fueled, metal lantern, wires protecting the glass chimney) from a nail just inside the door, well away from the perch.  It would provide a slight boost to the air temp in the coop.  

Chickens were a mix of "spent" factory egg layers (white leghorns with trimmed beaks and claws, very stupid birds, barely able to walk or scratch or feed themselves, apparently sold cheap in those days after their egg production would start to drop) and Rhode Island Reds that we raised from chicks bought as chicks.  The Reds had much larger combs and they did get a little bit of comb frostbite, but the Leghorns were much older birds.  My recollection is that we did get some mortality (one or two dead birds) among the leghorns the first winter when it got really cold.
 
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I'm a huge fan of open air coops. In my opinion,  ventilation is far more important than temperature.  Woods' open air chicken coop book is fantastic.  

Chickens in very cold weather get frostbite.  They get frostbite far worse if there is any moisture at all in their coop. I kept chickens one year in a 3 sided coop i built from straw bales.  It didn't have a front at all.  It was narrow and pretty deep, I believe it was about 4 feet wide and 12 feet or so deep. I built the roof from old doors stacked across and resting on the side walls.  I put more bales on top of them for insulation.  I used tree branches at the very back for roosts.  Since the front was entirely open and i never water my chickens in their coop,  it stayed perfectly dry.  With the roosts in the very back,  they didn't get drafts.  The opening was facing south and our really cold winds come from the north east.  We had temps -15 to -20 regularly,  and a low as -30f . The chickens were fine and the rooster had almost no frostbite on his comb.  The rooster in my traditional coop got worse frostbite.  

Woods' book talks about the minimum depth the coop can be to keep the chickens away from drafts with a completely open air coop.

Other people mentioned snow.  My chickens won't walk in snow.  They don't mind the cold but none of the breeds I have raised would walk in snow. I build open ended greenhouse type structures to give mine areas to walk without snow in the winter.  That is also where their water is,  never in the coop.
 
Pierre-Luc Drouin
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Timothy Markus wrote:Hi Pierre-Luc, and welcome to Permies.  

First, you know you get down to -40C at times.  It's OK, you can admit it. ;)  I know we get down to that most winters in SW ON, sometimes for a week or two.



Ok yes I will admit it, it gets colder :-)  

Timothy Markus wrote:Insulation and ventilation are pretty much mutually exclusive.  It's nice to insulate the floor of the coop, but the deep litter takes care of that.  Also, they'll happily roam around in the snow, so it's usually not a big deal.  The window doesn't need to be double glazed as any heat in the coop will go right out the top.  You also don't need a fancy cupola, just know that you need to get rid of the excess moisture and, as you know, keep the drafts off them.



Yes I know that ventilation works against insulation, but I was hoping that insulation could still help a bit if I manage to constrain the ventilation to the necessary amount. I am also aware that some of the features I was considering are not a necessity, but I want to minimize the risks of frostbites. Using the 4" pipe that goes up to the cupola combined with vertical air intakes appeared to be a good way for me to control the amount of ventilation in a way that is less sensitive to wind.

Timothy Markus wrote:I built a 4x6' coop out of 2x3 frame on 2' centers and 1/2" ply sides and roof.  I slanted the roof from 7' to 5' and kept my roosts at 2.5-3' so there was about 18" above the roosting hen to the 2" gap around the roof.  I just ran 2x3" joists on top of the coop frame for the gap and used 1/2" hardware cloth to keep out rats, weasels and opossums.  I had a couple of open cut outs that I covered with hardware cloth for more ventilation in the summer that I covered in the winter.  

Chickens come with a down coat, so they can stay pretty warm in winter.  I chose breeds with small combs, pea combs for preference.  I had a number of Chanteclers, our only Canadian breed, and they do very well in winter, as you'd expect.  I did end up with a couple of hens with big combs and they did get a little frostbite, but not bad.  In winter, they'll crowd together on the roost for warmth, squat down on their feet and tuck they're heads under their wings.  If you heat the coop and then lose power, they can't handle the abrupt change, so that'll kill them.  I took my girls through several winters like that without any issues except frozen water and eggs.  

I built a cookie tin waterer heater for underneath the plastic waterer, though I had to use 2 75W bulbs when it got down below -20C.  If you do use a cupola, make your air intake the same gaps just below the roof.  That way you'll have air stratification and it will come in under the roof and out the cupola, but the cupola should be at least 2' tall to get the right stack effect.  I've done a lot of attic ventilation analyses and stratification is  normally a bad thing, but good for livestock.  Like I said, though, it's needlessly complicated as a 2" gap 18" above chicken height (2-2.5' above the roost) works just fine.

edit:  I just wanted to add that you pretty much need to supplement light in our winters as they like 14 hours to lay well, even the Chanteclers, whatever anyone tells you. If you get them this year as ready to lay or pullets, you don't have to let them moult in the fall but next year let them moult naturally as the light wanes, then add light back gradually in the morning to get to 14 hours.  You want them to experience natural dusk as they'll naturally go home to roost and the light won't shut off all of a sudden, leaving them on the floor.



Thanks for all the helpful information. I want to stay away from active heating. Regarding what you are saying about air stratification, do you mean that it would be better, if I have a design that involves a cupola, that the air intakes be located right under the roof instead of lower in the coop? Even if the intakes do not cause the coop to be drafty due to the air moving only through a controlled stack effect? The 4" pipe that would go to my cupola would be about 4' tall...

I intend to bring power to the coop to supplement light, warm up water, control doors, the ceiling vent and to monitor the temperature/humidity. The roof will have a 45 degree pitch and face south so it is ideal for solar panels in the future.
 
Pierre-Luc Drouin
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Dan Boone wrote:My family had chickens in the 1970s in a log coop on the upper Yukon in Alaska, where it would get down below -50F and stay there for a couple of weeks at a time in January.  Under those conditions at least, ventilation was the enemy.  The goal was to seal that coop up as tightly as possible.  It was about six feet by eight feet, just tall enough for a person to stand inside, flat roof, made of about six inch logs, chinked with moss, plywood and tarpaper flat roof insulated with several inches of moss with Visqueen (plastic) vapor barrier.  There was sawdust on the floor of the coop but there was a screened bin under the perch to catch droppings.  Ammonia in the air was a definite issue, but never so much that it seemed to affect the health of the chickens.  I'm not saying any of this was a good way to do things, I'm just saying it was a way that worked and (mostly) kept chickens alive -- probably based on drawings/designs my parents saw in Mother Earth News magazine or Foxfire or a Rodale Press book.  

In the very coldest temperatures they would hang an old fashioned barn lantern (kerosine-fueled, metal lantern, wires protecting the glass chimney) from a nail just inside the door, well away from the perch.  It would provide a slight boost to the air temp in the coop.  

Chickens were a mix of "spent" factory egg layers (white leghorns with trimmed beaks and claws, very stupid birds, barely able to walk or scratch or feed themselves, apparently sold cheap in those days after their egg production would start to drop) and Rhode Island Reds that we raised from chicks bought as chicks.  The Reds had much larger combs and they did get a little bit of comb frostbite, but the Leghorns were much older birds.  My recollection is that we did get some mortality (one or two dead birds) among the leghorns the first winter when it got really cold.



Thanks for sharing your experience. -50F in Alaska is definitely more extreme than here. If you say that ammonia was an issue, do you think they were also affected by moisture as well under these conditions?
 
Pierre-Luc Drouin
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Trace Oswald wrote:I'm a huge fan of open air coops. In my opinion,  ventilation is far more important than temperature.  Woods' open air chicken coop book is fantastic.  

Chickens in very cold weather get frostbite.  They get frostbite far worse if there is any moisture at all in their coop. I kept chickens one year in a 3 sided coop i built from straw bales.  It didn't have a front at all.  It was narrow and pretty deep, I believe it was about 4 feet wide and 12 feet or so deep. I built the roof from old doors stacked across and resting on the side walls.  I put more bales on top of them for insulation.  I used tree branches at the very back for roosts.  Since the front was entirely open and i never water my chickens in their coop,  it stayed perfectly dry.  With the roosts in the very back,  they didn't get drafts.  The opening was facing south and our really cold winds come from the north east.  We had temps -15 to -20 regularly,  and a low as -30f . The chickens were fine and the rooster had almost no frostbite on his comb.  The rooster in my traditional coop got worse frostbite.  

Woods' book talks about the minimum depth the coop can be to keep the chickens away from drafts with a completely open air coop.

Other people mentioned snow.  My chickens won't walk in snow.  They don't mind the cold but none of the breeds I have raised would walk in snow. I build open ended greenhouse type structures to give mine areas to walk without snow in the winter.  That is also where their water is,  never in the coop.



Thanks for the book recommendation, I will look it up. Regarding the moisture issue, do you think that the deep liter method might be a bad idea for a non open air coop in cold temperatures? Also I am wondering how coops that exchange air through wall openings perform compared to coops that do it using a stack effect... In my area it tends to get really windy sometimes so this is why I was looking for a design that is not sensitive to wind.
 
Dan Boone
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Pierre-Luc Drouin wrote:
Thanks for sharing your experience. -50F in Alaska is definitely more extreme than here. If you say that ammonia was an issue, do you think they were also affected by moisture as well under these conditions?



I was a little kid, which is why I'm trying to recount my memories of how the coop was set up and that the chickens survived, without getting too detailed about their health details, which I probably never knew or was competent to assess; if it got discussed, those discussions might not have happened in my earshot.  I mention the ammonia because I remember the stink being fierce, and I know with my adult knowledge now that this is from ammonia, and that my mother was not managing the droppings as most do today in a deep/dry litter, but rather was letting them accumulate wet in a bin under the perch, screened with chicken wire to keep the birds out and to catch any eggs that the really-very-stupid leghorns (not their fault, they were raised in factory boxes where they never got to move) laid from the perch.  

There was not much egg production once the sun went down late November for its six week nap.  I don't think it ever completely stopped, but it dropped off to just a few eggs a day out of close to 20 hens.

I don't remember the ammonia being/causing any problems, health-wise, for the chickens.  Which is not to say that it didn't.  

Moisture, I don't think, was a problem.  Interior Alaska winters are extremely dry.  You can spot your air leaks in a cabin in cold weather by the streaks of frost around all the places warm wet air is leaking out.  The chicken coop, being below freezing but much warmer than outside, got some frost buildup on some of the interior surfaces; we would brush those frost crystals off the ceiling with our mittens (to avoid getting them down our necks) and they would mix with the sawdust on the floor.  I'm not sure how often the droppings box got shoveled out but I am fairly sure that sawdust got changed or at least layered fairly frequently, because we kids tracked through it to feed the chickens and check for eggs, and mom didn't want droppings tracked back into the house, even frozen.  

I know this is a long way away from your situation and design.  But I hope the knowledge that chickens are pretty extreme in what they can handle, helps reassure you that your much more modern designs will probably work out excellently!
 
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While we don't hit -20 here often in PA usa we we're at 0 a few times this winter an my chickens did fine. My run is 14*10 with old chain link fencing. I simply secured cheap plastic tarps to 3 of the sides from the direction of the wind to create a wind block an stop snow from being blown in and they have a coop box off the side that 3*3 with 3nest boxes but they seemed to prefer roosting out in the run most of the non windy nights. I also have my rabbit cages hanging in the run to use up the extra space an they also did just fine. We had a terrible winter here where it was 40 one day everything was wet then the next day 15 everything frozen solid.
Wind protection, dry area for them to walk in, an a shelter or coop to go into for the extreme days you should be good.
 
Timothy Markus
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Pierre-Luc Drouin wrote:
Thanks for all the helpful information. I want to stay away from active heating. Regarding what you are saying about air stratification, do you mean that it would be better, if I have a design that involves a cupola, that the air intakes be located right under the roof instead of lower in the coop? Even if the intakes do not cause the coop to be drafty due to the air moving only through a controlled stack effect? The 4" pipe that would go to my cupola would be about 4' tall...

I intend to bring power to the coop to supplement light, warm up water, control doors, the ceiling vent and to monitor the temperature/humidity. The roof will have a 45 degree pitch and face south so it is ideal for solar panels in the future.



As long as you don't have drafts, whatever you do will be fine if it provides enough ventilation.  The cupola and the air intakes will work but are, in my experience, needlessly complicated.  I got excellent ventilation from about a 2" screened gap just below the roof around all four walls with the low point of the roof pointed to the prevailing winds.  Ammonia will rise, so that's helpful.  If you're set on a cupola you can do what you've suggested or just use openings just under the roof, but you'd need a cupola of at least 2'above the intake in order to get enough stack effect for the ventilation to work.  If you put intake on the low side of the roof and the cupola at the top side, the rise will count towards that two feet.

I re-read your bit about the intakes:

An idea I have is to create vertical air intakes under the coop, which will sit 2' above the ground, and introduce that air in the coop about 1.5' above the floor (about 0.5' under the roost bars).  

 You want the air intake above the chickens, not below, as that would cause drafts from bottom to top.  I like air intake to be about 18" above the chickens when roosting.  I never bothered to calculate air changes, I just gave them enough ventilation to make sure it was fresh air.  If your roof only has a single slope, you need your air egress at the top of the slope.  If you put a cupola in the middle, the ammonia can pool in the upslope of the ceiling.
 
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